川西地区中二叠统栖霞组优质白云岩储层特征及形成机理  

Characteristics and formation mechanism of Qixia Formation(middle Permian) dolomite reservoirs in western Sichuan Basin

作　　者：冯明友[1] 张帆[1] 李跃纲[2] 张本健[2] 尹宏[2] 李波[1] 

机构地区：[1]西南石油大学地球科学与技术学院,成都610500 [2]中石油西南油气田分公司川西北气矿,四川江油621709

出　　处：《中国科技论文》2015年第3期280-286,共7页China Sciencepaper

基　　金：高等学校博士学科点专项科研基金资助项目(20125121110005)

摘　　要：为明确川西地区中二叠统栖霞组白云岩储层特征,探讨优质储层形成机理,通过显微镜、扫描电镜、阴极发光、物性测试等多种方法手段,结合野外露头、岩心、薄片、钻井等开展了系统研究。研究表明,川西地区栖霞组白云岩原始沉积物多为位于浅缓坡沉积环境的生物碎屑灰岩、生物灰岩及砂屑灰岩。储层岩石类型以细晶白云岩、中晶白云岩为主,其次为局部云化的豹斑状灰质白云岩。储集空间类型以晶间孔、晶间溶孔为主,其次为裂缝和孔洞。栖霞组储层属低孔、特低渗型储层,中-粗晶白云岩及颗粒白云岩储层物性较好。白云岩储层垂向上主要富集于栖霞组中上部,横向上延伸距离1~10km、单层厚度3~10m,平面上呈非规则带状展布。受沉积相、短期暴露溶蚀、多期云化作用、埋藏期溶蚀作用及构造裂缝复合影响,最终形成单个规模小但产能巨大的孔隙-裂缝型储层。The characteristics and formation mechanism of Qixia Formation （middle Permian） dolomite reservoirs in western Sichuan Basin was systematically investigated by means of microscopy, scanning electron microscopy, cathodoluminescence spectroscopy, and physical property test as well as outcrop, core, flake, and borehole. The carbonate sediment precursor of the dolo mites, interpreted from biogenic limestones, bioclast limestones and calcarenite, the association of facies indicates that grain limestones were deposited in shallow ramp environments on an carbonate ramp. Dolomite reservoirs are comprised of fine-crystalline dolomite, sucrosic dolomites, and subordinate interbedded Iimy dolomites and dolograinstones. Some dolostone reservoirs are contained entirely within grainstones. Others are capped by tight Leopard-spot limy dolomites that has been dolomitized locally. Reservoir space types are main concludes with intercrystalline pores, intercrystalline solution pores, secondly are vug and frac- tures. The reservoirs are most intense within the middleupper part and irregularly belt shaped bodies 1-10 km or so wide and commonly 3-10 m thick. Dolomites of the Qixia Formation in western part of Sichuan Basin form small but giant hydrocarbon res ervoirs. Porosity development within the medium- and coarse-crystalline dolomites, sucrosic dolomites and grained-dolomites, is a complex function of sedimentation, erosion of short term exposure, muti-dolomitization, and later leaching of calcareous components, tectonic fragmentation. During these times, complex dolomitization, concomitant leaching of calcite and fractures increased porosity of the dolomite reservoirs, formed effective pore-fracture reservoirs.

关 键 词：栖霞组 白云岩 储层 川西地区 

分 类 号：P618.13[天文地球—矿床学]